#include<stdio.h>
#define PI 3.14159
void main()
{
    float r,c,s;
    printf("请输入圆的半径(r):");
    scanf("%f",&r);
    c = 2 * PI * r;
    s = PI * r * r;
    printf("c = %6.2f,s = %6.2f\n",c,s);
}